Means and method for applying tension to sheet metal



Nov. 4, 1958 E. D. HOUGEN 2,853,872

MEANS AND METHOD FOR APPLYING TENSION TO SHEET METAL Filed Sept. 24,1954 I 2 Sheets-Sheet 1 IN V EN TOR.

[Viki-"77 0. #0061 /V BY 1 ,444 M ATTOR/VfYS Nov. 4, 1958 E. D. HOUGEN2,353,872

MEANS AND METHOD FOR APPLYING TENSION TO SHEET METAL Filed Sept. 24,1954 2 Sheets-Sheet 2 IN VEN TOR.

BY W MX MQEKM A TI'O/P/VA VS MEANS AND METHOD FOR APPLYING TENSION TOSHEET METAL Everett D. Hougen, Flint, Mich.

Application September 24, 1954, Serial No. 458,197

4 Claims. (Cl. 153-32) This invention relates to a device and a methodfor applying tension to sheet metal panels such as might be required,for example, in straightening a panel. It is an object of this inventionto provide a device which is adapted to be firmly secured to a sheetmetal panel and adapted for applying force to the panel in a directiongenerally parallel to the plane of the panel.

Another object of the invention is to provide a device and a method forstraightening a sheet metal panel by applying tension theretoeffectively and without bending or creasing the panel at the point ofapplication of the tension.

A further object of the invention resides in the provision of a devicewhich is readily adapted to be firmly secured to a portion of a sheetmetal panel which defines a curved plane or which is spaced inwardlyfrom the edges of the sheet metal panel without defacing the panel suchas by forming holes therein.

In the drawings:

Fig. l is a view show an arrangement which includes one form of thedevice of this invention and the manner in which the devices may be usedfor applying tension to a sheet metal panel such as an automobile top.

Fig. 2 is a vertical sectional view of one of. the devices shown in Fig.1.

Fig. 3 is a sectional view taken along the lines 33 in Fig. 2.

Fig. 4 is a perspective view of a portion of the arrangement shown inFig. 2.

Fig. 5 is a perspective view of a modified form of the device accordingto the present invention.

Fig.. 6 is a view illustrating the manner in which the device of Fig. 5may be secured to a sheet metal panel to be straightened and before theforce is applied thereto.

Fig. 7 is a view illustrating the arrangement of Fig. 6 after force isapplied to the device shown therein.

Fig. 8 is a view illustrating the manner in which the device shown inFig. 5 may be utilized for straightening a sheet metal panel adjacent asharply curved portion thereof.

Referring to Figs. 1 through 3, there is generally shown at 10 the toppanel of an automobile body which is being straightened utilizing themeansand the method of the present invention. The devices of the presentinvention which are designed to be secured to a sheet metalpanel areillustrated at 12. Each of these devices comprises a flat steel plate 14to the centre portion of which is secured a threaded stud 16. The devicealso includes a sleeve 18 provided on one side thereof wtih a threadedbearing member 20 engaged with the threads of stud 16. Bearing 20 issecured to sleeve 18 as by a welding at 22. Bearing 20 is disposed suchthat when threadedly engaged with stud 16, the axis of sleeve 18 isinclined slightly, preferably about 7, to the plane of plate 14. Theconnection between stud 16 and bearing 20 is in the nature of a swivelwhich enables sleeve 18 to rotate about the stud 16 as an 2,858,872 iatented Nov. 4, 1958 ice Sleeve 18 is provided with a plurality oflongitudinally spaced and diametrically aligned openings 24. The sleeves18 are adapted to receive the opposite cylindrical end portions 26 of ahydraulic jack '28. The cylindrical members 26 are provided with axiallyspaced openings 30 therein, a pair of which are adapted to be alignedwith a set of the openings 24' in each of the members 12. A pin or bolt32 extends through the aligned openings 24 and 30 to connect the members12 with the opposite ends of jack 28.

The members 12 are designed to be secured to a sheet metal panel such asis illustrated at 10 by soldering. Thus, the plate 14 is provided with asubstantially flat lower face 34. The face 34 of plate 14 may besoldered to the surface of a sheet metal panel such as indicated at 10readily and in a very simple manner. The'surfaces of the panel 10 towhich the members 14 are to be soldered and the faces 34 of the members14 are first cleaned and then tinned with solder. A thin layer of solderpreferably about /8 to 10, in thickness is applied to the tinned portionof the panel. Thereafter, the plate 14 and the panel are heated to atemperature above the melting temperature of the solder and the plate ispressed firmly into the layer of the solder on the sheet metal panel.The heat of the plate 14 raises the temperature of the solder layer suchthat the excess solder is squeezed out from between these members andforms a bead around the periphery of plate 14 such as is indicated at36. The panel and plate are then quenched with water. A very thin layerof solder 38 remains between the panel 10 and the face 34 of plate 14.This thin layer of solder provides a very firm bond between plate 14 andpanel 10.

After the members 12 are secured to the panel 10 as described, thecylindrical ends 26 of the jack 28 may be interengaged with the sleeves18 and pressure may be applied to the jack. This applies lateral forcesto the members 12 in opposite directions. These forces are transmittedto the panel 10 through the plates 14, and the portion of the panelbetween the two plates 1'4 is thus placed in tension. If the panel isbent between these two plates 14, it will tend to straighten as thetension is applied.

1 have found that when the plates 14 are secured to a sheet metal panelas described, it requires a lateral force of approximately 2,000 poundsper square inch to break the joint between the plate 14 andthe panel.Thus, it will be appreciated that even a relatively small plate such asshown at 14 when secured to the panel as described is capable ofwithstanding a tremendous force before the bond between the plate andthe panel is broken. For. example, if the plate 1.4 has. an area ofsay'6 square inches, a lateral force of approximately 12,000 poundsmay'be applied to the plate 14' before the bond between the plate andthe panel is broken. The device of this invention therefore provides avery convenient means. for applying a lateral force to a sheet metal.panel under circumstances where it is impracticable or impossible tofasten a jaw type clamp to the panel.

The inclination of the axis of bearing 20 to the axis of sleeve 18enables the application of a lateral force to a sheet metal panel in adirection slightly inclined to the plane of the panel. Under mostconditions in straightening sheet metal panels, it is desirable to applythe force to the panel in a direction inclined towards or away fromtheplane of the panel rather than. in a. direction parallel to thepanel. Most automobile panels are not perfectly flat. They are slightlyor sharply curved.

In Figs. 5 through 8, a modified form of the invention is illustrated.In this modification, the plate 40 of the device 39 that is adapted tobe soldered to a sheet metal panel is relatively thin and flexible asdistinguished from soldered to the sheet metal panel.

40 is preferably of rectangular shape; and at one end thereof, there issecured a reinforcement 42 in the form of a metal bar. The bar 42 may besimply welded across one end of plate 40 but is preferably secured tothe plate by bending the plate around the bar 42 as illustrated and thenWelding. A sleeve 18 such as previously described is swively connectedto the plate 40 by the stud 16 which is threaded into bar 42 at one endand into bearing 20 at its other end. In this form of the invention,bearing 20 may be disposed such that its axis is perpendicular to p theaxis of sleeve 18.

The plate 40 may be attached to a sheet metal panel by soldering insubstantially the same'manner as described above With reference to theplate 14. However, in the case of the plate 40, only the end portion 44is This is illustrated clearly in Figs. 6, 7 and 8. The soldered portionis indicated at 46 in Figs. 6 and 7 and at 48 and 50 in Fig. 8.

If desired, the portion 44 of plate 40 may be formed with openings 47through which the excess solder may be squeezed.

Referring now to Fig. 6, the device illustrated in Fig. 5 is shownsoldered to a bent sheet metal 52 which is desired to be straightened.Only one of the devices 39 p is illustrated. After the plate 40 issoldered as at 46 to the panel 52, one of the ends 26 of thehydraulicjack is secured to the sleeve 18. Before pressure is applied tothe jack, the plate 40 will lie generally flat against the panel 52assuming, of course, that the portion of panel 52 underlying plate 40 isalso generally flat (Fig. 5). However, after force is applied to theplate 40 through the member 26 and sleeve 18, the slight clearancebetween these members enables the plate 40 to flex upwardly away fromthe plane of panel 52 at the portion 54 adjacent the soldered section 46and downwardly towards plate panel 52 at the portion 56 of plate 40(Fig. 6).

Thus, because of the inevitable slight clearance between i the members26 and 18 and because of the direction in which the force is applied tothe plate, the plate is enabled to warp away from the underlying plate52.

Under such circumstances, if the plate 40 were a rigid to crease thepanel 52 inwardly along one edge of plate 1 40 and upwardly at theopposite edge of plate 40. The

. plate such as shown at 14 or if the plate 40 were soldered 1throughout its area to the plate 52, the inevitable cocking of thedevice 39 when the force is applied would tend flexibility of plate 40together with the fact that it is soldered to the underlying panel onlyat the end portion 44 thereof eliminates this difiiculty. The provisionof the device 39 with the flexible tension plate 40 also enablesattachment of the device to a sharply curved metal panel Q panel whichcomprises the steps of attaching only one end portion of one face of athin and flexible sheet metal plate to and in coplanar engagement with asurface portion of the panel at an area spaced from the distortedportion thereof, said attachment being eflected by soldering said faceportion of the plate flatwise to said surface portion of 4 the panelwith solder having a melting point substantially lower than the meltingpoint of the panel, detachably securing to the opposite end of the plateone end of a force applying member, anchoring the opposite end of theforce applying member relatively to the panel, applying to the solderedjoint between the plate and the panel by means of said force applyingmember a force in shear to straighten the distorted portion of thepanel, relieving the joint of said force and then removing said platefrom the panel by heating the plate to a temperature above the meltingtemperature of the solder and below the melting temperature of thepanel.

2. The method .called for in claim 1 wherein the plate is soldered tothe panel by tinning said one face portion of the plate with said solderand tinning and applying a layer of said solder to said area of thepanel, heating said layer of solder to the plastic state andsimultaneously heating said plate to a temperature above the meltingtemperature of the solder, pressing said plate while so heated into saidplastic layer of solder and immediately quenching the soldering jointthus formed by applying water directly against said plate while it isheld pressed against the panel.

3. The method of straightening a distorted sheet metal panel whichcomprises the steps of attaching only one end portion of one face of athin and flexible sheet metal plate to and in coplanar engagement with asurface portion of the panel at an area spaced from the distortedportion thereof, attaching only one end portion of one face of a secondthin and flexible sheet metal plate to and in coplanar engagement withanother surface portion of the panel on the opposite side of the damagedportion thereof, said plates being attached to said panel by solderingsaid face portions of the plates flatwise to said surface portions ofthe panel with solder having a melting point substantially lower thanthe melting point of the panel, extending a force applying member fromthe free end of one of said plates to the free end of the other plateand connecting said force applying member to said free ends, applying tothe soldered joints between said plates and thepanel by means of saidforce applying member a force in shear to straighten the distortedportion of the panel. relieving the joints of said force and thenremoving said plates from the panel by heating the plates to atemperature above the melting temperature of the solder and below themelting temperature of the panel.

4. The method called for in claim 3 wherein said plates are soldered tothe panel with the free ends thereof extending generally in oppositedirections and force is applied to said plates so that the portion ofthe panel therebetween is tensioned.

References Cited in the file of this patent UNITED STATES PATENTS

